In the past, the art of capturing an image of an outer circumference edge part of a semiconductor wafer and using that image to inspect the outer circumference edge part for damage, projections, and other conditions has been proposed. For example, the art described in Patent Literature 1 is a system for inspecting the state of the outer circumference edge part of a semiconductor wafer where the outer circumference edge part is comprised of an outer circumference end face, a first outer circumference bevel surface slanted at an outer edge of a first main surface, and a second outer circumference bevel surface slanted at an outer edge of a second main surface. This inspection apparatus arranges a camera lens facing the outer circumference edge part of the semiconductor wafer and forms an image of the outer circumference end face and forms images of the first outer circumference bevel surface and second outer circumference bevel surface on an imaging surface through the camera lens so as to be able to capture the outer circumference end face, first outer circumference bevel surface, and second outer circumference bevel surface all together.
Further, in the art described in Patent Literature 1, the length of the light path from the outer circumference end face of the semiconductor wafer to the imaging surface and the lengths of the light paths from the first outer circumference bevel surface and second outer circumference bevel surface to the imaging surface differ. It is difficult to form an image of the outer circumference end face and images of the first outer circumference bevel surface and second outer circumference bevel surface on a single imaging surface. In consideration of this, a correction lens is arranged between the outer circumference end face of the semiconductor wafer and the camera lens to make the lengths of the light paths match.                Patent Literature 1: International Publication No. 2006/059647 pamphlet        